Forestry machines in the form of disk saw felling heads (DSFH, which includes wheeled feller bunchers and tracked feller bunchers) have a saw head at the front end of the machine with a spinning disk at the bottom of the saw head. A plurality of cutting teeth are mounted to the periphery of the spinning disk at spaced apart intervals. The disk is massive and acts as a flywheel which is spun up to operating speed by a hydraulic pump and motor circuit. The saw cuts trees by kinetic energy, not hydraulic power. Thus, rotational speed of the disk is needed and recovery of rotational speed is important to the ability to cut the next tree. Cutting pulls down the speed of the saw by using energy.
Users of DSFH desire a reliable and automatic way to count trees that are cut. Existing methods of counting trees require manual input or are not highly accurate. Typical automatic methods include either monitoring clamp cycles or saw speed pulldown, or a combination of both. The current estimated accuracy of such tree counting systems is approximately 80%.
Monitoring clamp cycles produces inaccuracy because operators sometimes cycle the clamps for reasons other than tree harvesting (such as repositioning of trees on the ground, adjusting the grip on existing trees in the head, etc.). Monitoring saw speed pulldown produces inaccuracy because trees below a certain diameter do not decelerate the saw enough for the system to reliably register a cut.
What is needed in the art is a feller buncher with an accurate and reliable indicator of how many trees have been cut.